Excessive torque is a significant problem in circular knitted fabrics. "Torque" is when the wale line and the course line are not at a 90.degree. angle after washing. In garments this effect is manifest by side seam movement as well. While excess torque can be a problem in most circular knitted fabrics, it is particularly significant for jacquard cotton construction fabrics. Garment manufacturers require that the torque be kept below 8%, but this can be a real problem in producing jacquard cotton construction fabrics.
A standard technique used by many fabric manufacturers to produce cotton jacquard construction fabrics is to use 100% Z-twisted ring spun yarn of substantially 100% cotton. It has been known, per se, to use Z-twist and S-twist yarns together to reduce torque, but is not normally employed because a non-smooth fabric appearance results; that is, in one course line the stitch slants to the left, and in the next course line the stitch slants to the right. For solid piece dyes or solid area dyes, this course by course slant effect essentially makes the construction unmarketable to any broad customer base at all. Also, current methods for making jacquard constructions that do not have the course by course slant effect problem are either inconsistent in being able to meet the less than 8% torque requirement (many batches have a torque of 10-13%), and/or results in weak fabrics, which of course means poor quality.
According to the present invention, it is possible to solve the course by course slant effect problem while consistently achieving a torque below 8%. This is accomplished, according to the invention, by using differently colored yarns in different courses. In practicing the invention, it is possible to produce fabrics that have very low torque values, on the order of 0-2%, while unexpectedly realizing numerous other advantages. For example, the fabrics and garments according to the invention have a much softer hand than is normal because little or no stiffening agent is used to finish the fabric to minimize curling (as is done in conventional constructions which minimize curling). The fabrics according to the invention lay very flat, and realize significant improvement in the finishing process for bow/bias/hook because the fabric is straight going to the finishing frame, and the torque does not affect the edge of the fabric for hook after slitting. Also, the garment formation process is simpler because the garment lays flatter during garment formation. Also, the garment lays flatter after washing because of little, if any, torque in the fabric.
According to one aspect of the present invention a method of making a jacquard construction fabric is provided, comprising the following steps: (a) Spinning and Z-twisting a first at least primarily cotton yarn. (b) Spinning and S-twisting a second at least primarily cotton yarn. (c) Dyeing the first yarn a first color. (d) Dyeing the second yarn a second color different than the first color. And (e) knitting a jacquard construction fabric using the first and second yarns in a ratio of about 30-70% Z-twist yarn to about 70-30% S-twist yarn, so that a fabric having a torque below 8%, and substantially no discernible course by course slant effect, is produced.
The method comprises the further steps of: spinning and either Z or S twisting a third at least primarily cotton yarn, and (g) dyeing the third yarn a third color, different than the first and second colors; and wherein step (e) is practiced by knitting a three color jacquard construction fabric using the first, second, and third yarns.
Steps (a) and (b) and (f) are preferably practiced by ring spinning, and producing substantially 100% cotton yarns having a yarn size for each yarn of between 8/1's to 40/1's cotton, and the sizes of the first and second yarns not differing by more than two sizes. There also typically are the additional steps of finishing the fabric (which is simpler and improved as described above, e.g. substantially without stiffener) and making the fabric into a garment (which is also simplified due to the lay-flat nature of the garment). The method steps are typically practiced to produce a fabric with a torque of less than 5%, e.g. between about 0-2%, and is practiced so that the colors are distinct enough so that there is substantially no discernible course by course slant effect in the resulting garment either.
According to another aspect of the present invention, a fabric is provided comprising the following components: First and second yarns providing a jacquard knit construction fabric, having a torque of less than 8% and substantially no discernible course by course slant effect. The first yarn comprising a first color Z-twisted at least primarily cotton yarn. The second yarn comprising a second color, different than the first yarn, S-twisted at least primarily cotton yarn; and the fabric having a ratio of about 30-70% Z-twist yarn to about 70-30% S-twist yarn. The fabric may be provided in combination with conventional stitching forming the fabric into a finished garment, and the fabric and resulting garment preferably have a torque of less than 5%, e.g. between about 0-2%. The yarns are preferably ring spun substantially 100% cotton yarns. The fabric may further comprise a third at least primarily cotton either S or Z-twisted yarn having a third color different from the first and second colors, the fabric jacquard knit construction comprising the first, second and third yarns.
According to another aspect of the present invention a fabric is provided comprising: First, second and third yarns in a jacquard knit construction fabric, the fabric having a torque of less than 5%. The first yarn comprising a Z-twisted substantially 100% cotton ring spun yarn. And the second and third yarns each comprising an S-twisted substantially 100% cotton ring spun yarn, or a combination of S- and Z-twisted yarns, and wherein the fabric has substantially no discernible course by course slant effect. Equivalent to this construction is one where the first yarn is S-twisted and the second and third yarns are Z-twisted. The fabric is preferably used in combination with stitching to form a finished garment, and the yarns typically comprise at least two different colors.
Under some circumstances it is possible to produce a fabric using even more than three different color yarns.
While the invention may be practiced so that at least about 30% of the yarns are of one twist (e.g. S-twist) with the other about 70% the other twist (e.g. Z-twist); the best performance is achieved when about 50% (e.g. 45-55%) of each type of yarn is provided. Typically, the size of the yarn is not a result effective variable, as long as the first and second yarns are of approximately the same size, so that they have comparable innate twist forces that can be exerted. However it is preferred that the yarns have a size between 8/1's to 40/1's (e.g. 18/1's to 28/1's) cotton, and the Z and S twist yarns do not differ by more than a size of two (e.g. 20/1's and 22/1's). For the three color construction, each color is preferably in the amount of at least about 20%, and the amount of Z-twist compared to S-twist yarn is again in the area of between about 30-70% and 70-30%.
It is the primary object of the present invention to provide for an effective fabric or garment, and method of production thereof, which has low torque, good strength, and no discernible course by course slant effect. This and other objects of the invention will become clear from an inspection of the detailed description and from the appended claims.